As @bastnic said in #35268:

On every request and for every data type, we possibly traverse a lot of normalizers to check which one should be used (using support(de)Normalization methods.
It has be optimized a lot with the addition of CacheableSupportsMethodInterface but we could warm it for all entities and DTO that we can found.

⚠️ It's a first try to implement this feature and I don't know if the structure is really good. Feel free to give me feedbacks!

So, how it works?

The Serializer now uses a NormalizerChooserInterface which give two methods: chooseNormalizer and chooseDenormalizer. The code written in the Serializer is a little bit the same.
On top of that, the CacheNormalizerChooser decorates the default NormalizerChooser and give the ability to cache the results via the cache interface.

Moreover, I have introduced a new cache warmer called SerializerNormalizerChooserCacheWarmer. It will fetch all the providers defined with the interface CacheNormalizationProviderInterface and warm the cache with the CacheNormalizerChooser.

Cache normalization provider example

class PostCacheNormalizationProvider implements CacheNormalizationProviderInterface
{
    public function provide(): \Generator
    {
        yield ['json', new Post()];
        yield ['yaml', new Post()];
        yield ['json', new Author()];
    }
}